1. Field of the Invention
The present invention relates to a drawing apparatus as a terminal device for inputting an image on the display screen of a display apparatus or the like of a computer.
2. Description of Related Art
There are known drawing apparatuses which are designed to detect characters, a figure or the like, drawn on a tablet as an imaginary paper using a pen-like input device, and to display what has been input on a display.
FIGS. 1A and 1B are schematic diagrams showing a conventional drawing apparatus. As shown in FIG. 1A, the drawing apparatus has an input pen 101 comprised of a coordinate indicator, and a plate-like tablet 102 comprised of a digitizer. As the input pen 101 is moved and slid on the tablet 102, the coordinates of the moving pen 101 are detected and are supplied to an unillustrated computer or the like so that the locus of the moving pen 101 is displayed on the display screen of a monitor or the like to draw whatever has been input.
The thickness (width) of the locus can be changed by drawing software which runs on the computer, so that a user can make drawing while properly selecting the thickness of the locus as needed.
Even though the thickness of the locus is selected from various types available, the sliding resistance of the input pen 101 with its core 103 slid on the tablet 102 does not vary and the touch or the writing sensation the user feel through his hand does not change. This gives the user awkward feelings in the drawing operation.
When one actually writes characters on paper with a writing brush or the like, he can write them while adjusting the thickness of a line by controlling the stroking pressure. With the use of the conventional input pen as shown in FIG. 1B, however, when the core 103 made of metal or the like is pressed against the tablet 102, the stroking pressure is detected by taking the deformation of a pressure sensor 104 as a change in electric capacitance. Since the deformation of the pressure sensor 104 is so subtle that there hardly is a stroke of the input pen to the tablet 102.
Further, the deformation characteristic of the input pen with respect to the level of the stroking pressure is fixed. Therefore, the user cannot sense a non-linear deformation characteristic of each writing brush with respect to the level of the stroking pressure, which the user feels through his hand when actually using various kinds of writing brushes, or the brush strength or the like which varies from one brush to another. Thus, the writing sensation does not change, which still gives the user awkward feeling in the drawing operation.